Grazing for Bog Turtle ( Glyptemys muhlenbergii ) Habitat Management: Case Study of a New York Fen

摘要

Groundwater-fed wet meadows and rich fens with low, open vegetation form the core habitats of rare Bog Turtles (Glyptemys muhlenbergii) in the northern part of their range in North America. Under current conditions, these habitats tend to become overgrown with taller vegetation in the absence of management. In agricultural and post-agricultural landscapes, managers sometimes use livestock grazing to improve and maintain habitat quality for Bog Turtles, despite insufficient knowledge about how specific practices affect both Bog Turtles and nontarget species. To further our understanding of such effects, we present results from a single wetland complex in New York, USA, which we managed primarily with cattle grazing over four and a half growing seasons. Management effectiveness was assessed by monitoring Bog Turtle nest placement, habitat use via radio tracking, and vegetation structure and composition change in permanent plots. Nest locations varied among years, with all nests placed in grazed or recently grazed areas. Individual turtles maintained, and in some cases expanded, their ranges in grazed areas during spring and summer, although they continued to avoid one (grazed) area with apparently unsuitable soils, and increasingly used cattle exclusion areas for fall and overwintering habitat. Plant species richness and the cover of native plants and fen-indicator plants increased in grazed areas, while cover of nonnative species did not. Grazing appeared to improve Bog Turtle habitat without negatively affecting fen and other wetland vegetation at this site, and we propose several specific management recommendations based on our results.